
<%@ page
    import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" pageEncoding="UTF-8"%>
<%@ page import="java.io.OutputStream"%>
<%!
Color getRandColor(int fc, int bc){
     Random random = new Random();
     if (fc > 255)
         fc = 255;
     if (bc > 255)
         bc = 255;
     int r = fc + random.nextInt(bc - fc);
     int g = fc + random.nextInt(bc - fc);
     int b = fc + random.nextInt(bc - fc);
     return new Color(r,g,b);
     } %>
<%
try {
    response.setHeader("Pragma", "No-cache");
    response.setHeader("Cache-Control", "No-cache");
    response.setDateHeader("Expires",0);
    int width = 60, height = 20; 
    //建立BufferedImage对象，指定图片的长度宽度和色彩
    BufferedImage image = new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB);
    OutputStream os = response.getOutputStream(); 
    //取得Graphics对象，用来绘制图片
    Graphics g = image.getGraphics();
    //绘制图片背景和文字，释放Graphics对象所占用的资源
    Random random = new Random();
    g.setColor(getRandColor(200,250));
    g.fillRect(0, 0, width, height);
    g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
    g.setColor(getRandColor(160,200));
    
    for (int i=0;i<155;i++){
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        int x1 = random.nextInt(12);
        int y1 = random.nextInt(12);
        g.drawLine(x, y, x + x1, y + y1);
    }
    String sRand="";
    for (int i=0 ; i<4 ; i++){
       String rand = String.valueOf(random.nextInt(10));
       sRand += rand;
       g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
       g.drawString(rand, 13*i+6, 16);
    }
    session.setAttribute("rand",sRand);
    g.dispose();
    ImageIO.write(image,"JPEG",os);
    os.flush();
    os.close();
    os = null;
    response.flushBuffer();
    out.clear();
    out = pageContext.pushBody();
    }
    catch (IllegalStateException e)
    {System.out.println(e.getMessage());
    e.printStackTrace();
    } 
    %>
